Image intensifier tube

ABSTRACT

One or more image intensifier tubes are arranged on the axis of a unitary body in which the tube or tubes and a high voltage supply are embedded in a synthetic resin plastic. Optical window members are affixed to the outer image intensifier end surfaces. At at least one end of the body the adjacent image intensifier tube end has an outward flange. At the same end of the unitary body is a ring of rigid non-extensible material with its internal surfaces embedded in the plastic which provides a firm annular end surface for attaching the unitary body to a housing. This ring has a flange located inwardly of the flange of the adjacent intensifier tube end, so that the space between the intensifier tube end and the rigid ring is filled by a thin annular mass of the embedding plastic, so that the attachment ring firmly locates its end of the intensifier and the optical window with respect to the housing. The other end of the intensifier is positioned transversely in the housing by a freely sliding fit of the unitary body to the housing that permits relative axial movement resulting from thermal expansion and the like.

United States Patent [191 [111 3,882,340 Jonker May 6, 1975 IMAGE INTENSIFIER TUBE [57] ABSTRACT [7 5] Inventor: Wilhelm Richard Jonker, Vries,

Netherlands Assignee: B.V. Delft Electronics producten a Dutch, Roden, Netherlands Filed: Nov. 30, 1973 Appl. No.: 420,387

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 1/l959 Portenier et a1. 250/239 6/1973 Babb et a1 250/213 R Primary ExaminerR. V. Rolinec Assistant Examiner-E. R. La Roche Attorney, Agent, or Firm-Flynn & Frishauf One or more image intensifier tubes are arranged on.

the axis of a unitary body in which the tube or tubes and a high voltage supply are embedded in a synthetic resin plastic. Optical window members are affixed to the outer image intensifier end surfaces. At at least one end of the body the adjacent image intensifier tube end has an outward flange. At the same end of the unitary body is a ring of rigid non-extensible material with its internal surfaces embedded in the plastic which provides a firm annular end surface for attaching the unitary body to a housing. This ring has a flange located inwardly of the flange of the adjacent intensifier tube end, so that the space between the intensifier tube end and the rigid ring is filled by a thin annular mass of the embedding plastic, so that the attachment ring firmly locates its end of the intensifier and the optical window with respect to the housing, The other end of the intensifier is positioned transversely in the housing by a freely sliding fit of the unitary body to the housing that permits relative axial movement resulting from thermal expansion and the like.

9 Claims, 1 Drawing Figure llZY/ 11 PAIENIEnmsisns 5, 2,340

15 19 hlkwr (I? 9 12 k/l/IIAI WWI/Z1 11 {x g WW 3 10 fig [ml 5 IMAGE INTENSIFIER TUBE The invention relates to an image intensifier tube device, the components of which, one or more image intensifier tubes and a high voltage means, are moulded in a plastic body, which body is incorporated in a plastic housing, each end of which having a cover with an aperture through which, via optical windows, which are rigidly fixed to the image intensifier tubes, respectively a fluorescent screen can be observed and a photosensitive layer can be struck by radiation.

In known devices one end of the housing has a cover, which is rigidly fixed to the housing or which has been formed in one piece with the housing, the cover having an aperture through which via an optical window a fluorescent screen or a photo-sensitive layer can be observed. The opposite end of the housing has a cover which is fixed to the housing as by threading and which keeps the body from a movement in an axial direction.

Devices of this art in practice mostly cooperate with optical systems, respectively to form an image of a scene on the photo-sensitive layer and to observe the image on the fluorescent screen, both optical systems usually having a common optical axis which is therefore the axis of the device. It is important that at least one of the following distances has a constant value:

firstly, the distance between the optical window in front of the photo-sensitive layer and the related optical system, and

secondly, the distance between the optical window in front of the fluorescent screen.

In practice these distances are determined mechanically by the distances between the covers and the related optical systems.

A drawback of the known devices is related to the fact that the distance in the direction of the axis of the device between the outer surface of the optical windows and the outer surface of the covers is changing as a function of l) the temperature of the surroundings, (2) the static mechanical load on the housing and its covers which load results from the clamping of the device in axial direction, (3) the dynamical mechanical load on the housing and its covers, which load results from shaking, bumping, vibrating, etc. The variation in the distance in axial direction between the outer surface of the windows and the outer surface of the cover also results from circumstances of changing temperature of the surroundings, static and dynamic loads in the past.

According to the invention an image intensifier tube device is provided in which at one end of the housing the distance in axial direction between the outer surface of the optical window and the outer surface of the cover has a substantially constant value and in which the variation of said distance are kept within micron.

The image intensifier tube device according to the invention is characterized in that at one end of the housing means are provided to maintain a predetermined distance in axial direction between the outer surface of the window and the outer surface of the cover at said end of the housing, the end of the body at the opposite end of the housing being supported transversely of the axis of the device so as to be movable in the axial direction relative to the housing.

In a preferred embodiment of the image intensifier tube device according to the invention, the means to maintain a predetermined distance comprise a ring partly embedded in the body at one end of the body of plastic, which ring is of a rigid, non-deformable material, the distance in the axial direction of the device between the outer surface of the optical window at that end of the device and the non-embedded outer surface of the ring having a predetermined value, said nonembedded surface of the ring resting against the inner surface of the cover at that end of the device and being fixed to said inner surface, the thickness of the cover having a predetermined value, the cover being fixed to the housing, the inner curved surface of the embedded ring having a shoulder, which cooperates with a flange on an image intensifier tube to form a chamber which is filled with plastic, the opposite end of the body being supported transversely of the axis and movable in the axial direction in the housing. To ensure a safe use of the device, means are provided to prevent flash-over and electrical discharge, even under extreme temperatures and of the surroundings.

The invention will be further elucidated by reference to the drawing.

The single FIGURE of the drawing shows an embodiment of the device according to the invention.

In the FIGURE a housing 1 of a rigid synthetic resin plastic is shown, in which a body 2 of synthetic resin plastic is placed. A number of image intensifier tubes, of two of which the extremities are shown, and a highvoltage supply, not shown, are moulded in the body 2. At 3 the extremity with the fluorescent screen of one of the image intensifier tubes is shown.

The optical window 4 is placed in front of the notshown cathode of the image intensifier tube at that end of the body 2. At 5 the end with the photo-sensitive layer of one of the image intensifier tubes is shown.

The optical window in frori't of the photo-sensitive layer is shown at 6. At 8 the ring which is embedded in the body 2, is shown. Near the end of the image intensifier tube of which extremity 5 is shown, a flange 9 is mounted to said tube, which flange 9 cooperates with the shoulder 10 of the ring 8 to form a narrow chamber 11, which is filled with synthetic resin plastic. The end of the housing 1, near the ring 8 is closed with a rigidly fastened cover 12. The cover 12 is made of a metal. In the opposite end of the body 2 near the image intensifier tube part 3 of ring 13 of a rigid synthetic resin plastic is moulded in the body 2. The cross-section of this ring 13 has a Z-form, the free and of one of the horizontal flanges 14 resting against the inner wall of the housing 1. The outer surface 15 and 15 are not embedded in the plastic of the body 2.

As further is shown in the FIGURE, the window 4 is embedded in the body 2, the window being left uncovered by the embedding plastic provided for the body 2. The ring 13 is enclosed by the cover 18, a glass plate 17 being placed between ring 14 and cover 18. This construction ensures freedom for this end of the body 2 to move relative to the housing '1 in the axial direction of the device.

It will be understood that under circumstances of changing temperatures, shocks, vibrations and static loads, the axial distance between the outer surface 19 of cover 12 and the outer surface 7 of window 6 will be influenced only by the plastic in the narrow chamber 11 between flange 9 and shoulder 10 of the ring 8. By giving the dimensions of this chamber 11 predetermined small values, the changes in said axial distance can be kept very small. Furthermore the well-known behaviour of some plastics, that is being deformable but not compressible, together with the choosen form of chamber 11 will ensure a constant axial distance under circumstances of vibration, shock and mechanical loads.

A predetermined axial distance between the outer surface 16 of ring 8 and the outer surface 7 of window 6 can easily be adjusted during the manufacturing of the tube, by providing means in the mould, which is used to mould in the image intensifier tubes and the high-voltage device, to place and keep the ring 8 in the right position in respect to the surface 7.

It will be understood that the same provisions can be made, conversely at the other end of the device, in which case the opposite end of the device, with the photo-sensitive layer is, supported transversely and movable in axial direction relative to the housing.

I claim:

1. Image intensifier device comprising:

a housing of rigid synthetic resin plastic provided respectively at opposite ends with openings centered on a common axis, at least a first of said openings, located at a first end of said housing, being formed in a cover provided on the first end of said housing;

a unitary body coaxial with said axis composed of at least one image intensifier tube coaxial with said axis and coaxial optical windows at the axial ends of said body adjacent image intensifier tube end surfaces on which they are respectively affixed and also high voltage power supply means consisting of components all located off said axis, all of the foregoing components of said body being embedded and surrounded, except for end surfaces of said tube or tubes and of said optical windows, in a synthetic resin plastic, said opening in said cover clearing the adjacent optical window and the other of said openings clearing the adjacent end of said unitary body;

at least the intensifier tube end adjacent said cover having a flange;

a ring of rigid non-deformable material arranged to provide a rigid annular end surface of said unitary body for attachment to said cover, said ring having an internal flange embedded in said embedding synthetic resin plastic and located axially inwardly of said flange of said intensifier tube end;

said ring being spaced from said tube end and its flange by an annular mass of said embedding plastic, whereby the positioning of said ring relative to said cover substantially fixes the position of said tube end, and the optical window adjacent thereto relative to said cover, said ring being affixed to said cover, and

means near the end of said unitary body remote from said first end of said housing for supporting said unitary body transversely to said axis in said housing while freely permitting axial movement of said end of said body relative to said housing.

2. Image intensifier device as defined in claim 1 in which said annular mass of said embedding plastic between said ring and said flange of said intensifier tube end has a thickness substantially smaller than the dimension of said annular mass in the axial direction.

3. Image intensifier device as defined in claim 2 in which said optical windows are centered by a lip of said embedding plastic extending around the adjacent intensifier tube end.

4. Image intensifier device as defined in claim 3 in,

which the external surface of said lip adjacent the optical window protruding through said cover is flush with said annular end surface of said ring of rigid material.

5. Image intensifier device as defined in claim 1 in which said means for transversely supporting said unitary body includes at least a belt of rigid nondeformable material disposed for sliding engagement with an internal surface of said housing.

6. Image intensifier device as defined in claim 5 in' which said means for transversely supporting said unitary body includes a rigid annular body partly embedded in said embedding material having an S-shaped profile including an outwardly extending flange disposed for freely sliding on an internal surface of said housing, a cylindrical intermediate portion and an internally extending flange and in which a cap ring is provided for securing protective glass plate between said inwardly extending flange and said cap ring in a position protecting the outer surface of the adjacent optical window.

7. Image intensifier device as defined in claim 1 in which the intensifier tube end adjacent said first end of said housing is the end of an image intensifier in which a photosensitive surface is provided. I

8. Image intensifier device as defined in claim 1 in which the image intensifier end adjacent said first end of said housing is the end of an image intensifier in which a fluorescent viewing screen is located.

9. Image intensifier device as defined in claim 1 in which a plurality of image intensifier tubes are arranged coaxially adjacent in said unitary body for operation in cascade. 

1. Image intensifier device comprising: a housing of rigid synthetic resin plastic provided respectively at opposite ends with openings centered on a common axis, at least a first of said openings, located at a first end of said housing, being formed in a cover provided on the first end of said housing; a unitary body coaxial with said axis composed of at least one image intensifier tube coaxial with said axis and coaxial optical windows at the axial ends of said body adjacent image intensifier tube end surfaces on which they are respectively affixed and also high voltage power supply means consisting of components all located off said axis, all of the foregoing components of said body being embedded and surrounded, except for end surfaces of said tube or tubes and of said optical windows, in a synthetic resin plastic, said opening in said cover clearing the adjacent optical window and the other of said openings clearing the adjacent end of said unitary body; at least the intensifier tube end adjacent said cover having a flange; a ring of rigid non-deformable material arranged to provide a rigid annular end surface of said unitary body for attachment to said cover, said ring having an internal flange embedded in said embedding synthetic resin plastic and located axially inwardly of said flange of said intensifier tube end; said ring being spaced from said tube end and its flange by an annular mass of said embedding plastic, whereby the positioning of said ring relative to said cover substantially fixes the position of said tube end and the optical window adjacent thereto relative to said cover, said ring being affixed to said cover, and means near the end of said unitary body remote from said first end of said housing for supporting said unitary body transversely to said axis in said housing while freely permitting axial movement of said end of said body relative to said housing.
 2. Image intensifier device as defined in claim 1 in which said annular mass of said embedding plastic between said ring and said flange of said intensifier tube end has a thickness substantially smaller than the dimension of said annular mass in the axial direction.
 3. Image intensifier device as defined in claim 2 in which said optical windows are centered by a lip of said embedding plastic extending around the adjacent intensifier tube end.
 4. Image intensifier device as defined in claim 3 in which the external surface of said lip adjacent the optical window protruding through said cover is flush with said annular End surface of said ring of rigid material.
 5. Image intensifier device as defined in claim 1 in which said means for transversely supporting said unitary body includes at least a belt of rigid non-deformable material disposed for sliding engagement with an internal surface of said housing.
 6. Image intensifier device as defined in claim 5 in which said means for transversely supporting said unitary body includes a rigid annular body partly embedded in said embedding material having an S-shaped profile including an outwardly extending flange disposed for freely sliding on an internal surface of said housing, a cylindrical intermediate portion and an internally extending flange and in which a cap ring is provided for securing protective glass plate between said inwardly extending flange and said cap ring in a position protecting the outer surface of the adjacent optical window.
 7. Image intensifier device as defined in claim 1 in which the intensifier tube end adjacent said first end of said housing is the end of an image intensifier in which a photosensitive surface is provided.
 8. Image intensifier device as defined in claim 1 in which the image intensifier end adjacent said first end of said housing is the end of an image intensifier in which a fluorescent viewing screen is located.
 9. Image intensifier device as defined in claim 1 in which a plurality of image intensifier tubes are arranged coaxially adjacent in said unitary body for operation in cascade. 